Multidose jet injector



March 3, 1964 A. w. KATH MULTIDOSE JET INJECTOR 2 Sheets-Sheet 1 FiledOct. 2, 1961 ATTORNEYS.

March 3, 1964 A. w. KATH MULTIDOSE JET INJECTOR 2 Sheets-Sheet 2 FiledOct. 2. 1961 l/V VEN TOR.

ATTORNEYS.

United States Patent 3,123,970 MULTEOSE SET INJECTOR Alfred W. Kath,Grosse Pointe, Mich, assignor to R. P. Schercr Corporation, Detroit,Mich, a corporation of Michigan Filed Get. 2, 1961, Ser. No. 142,083Ciaims. (Cl. 128-173) This invention relates to a hand operatedhypodermic injector capable of administering one injection afteranother. In some respects it is similar to the multidose injector ofVenditty and Hammer Patent No. 2,928,390 and in other respects similarto the multidose injector of the Venditty and Kath application SerialNo. 49,662 filed August 15, 1960 but does not require electric and/ orhydraulic power, being instead hand operated as by a crank.

One object of the invention is to provide an injector which willdischarge medicament from a tiny orifice in a minute stream or jet bymeans of springs which are compressed by a crank and which deliver aninitial high pressure discharge because of impact which causes the jetstream to distend the skin and force the medicament to a predetermineddepth beneath the surface thereof, followed by a lower pressure, steady,follow-through jet as the springs expand for completing transfer of theremaining medicament of the dose at the predetermined depth.

Another object is to provide an improved multiple dose unit which issimple in operation, of sturdy construction and which may quickly beactivated by rotation of a crank, and the injection then administered bydepression of a trigger whereupon a valve may be adjusted to a fillingposition and the crank further rotated to initial position forcompleting the injection cycle. The valve is automatically adjusted todischarge position by rotation of the crank near the completion of theactivating operation.

A further object is to provide an assembly in which a precompressedspring is held in precompressed position, and cam and roller meansoperated by a crank further compresses the spring assembly while it islatched in a predetermined position whereupon release of the latch bydepression of a trigger will permit the spring assembly to expand andadminister the injection.

Still a further object is to provide a medicament plunger which has alost motion connection with a springdriven plunger so that the initialexpansion of the spring assembly when the latch is released etiects animpact blow against the medicament plunger after which the rest of theexpansive force of the spring assembly is utilized to force themedicament plunger forward in its chamber for effecting the completionof the hypodermic injection. The initial high pressure produced byimpact produces a very small puncture through the epidermis and thelower pressure, steady, follow-through jet expels the remaining liquidinto the underlying tissue through the puncture.

An additional object is to provide against damage produced by shock whendry firing the injector comprising means to trap air ahead of theexpanding spring assembly and relieve the air slowly through an airbleeder hole.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mymultidose jet injector, whereby the objects above contemplated areattained, as hereinafter more fully set forth, pointed out in my claimsand illustrated in detail on the accompanying drawings, wherein:

FIG. 1 is a side elevation of a hypodermic injector embodying my presentinvention showing the parts in an initial position.

FIG. 2 is a front elevation thereof.

satanic Patented Mar. 3, 1964 FIG. 3 is an enlarged plan view partly insection on the line 3-3 of FIG. 1 showing internal details ofconstruction and operation, the parts being in an initial or at restposition.

FIG. 4 is a vertical sectional view on the line 4-4 of FIG. 3 showingthe spring assembly compressed and the medicament valve partiallyoperated from the refill position of FIGS. 1, 2 and 3.

FIG. 5 is a similar view showing the crank rotated to a position forcompleting the movement of the valve to medicament discharge position,and a spring plunger released for starting the injection operation.

'FIG. 6 is a sectional line on the line 6 of FIG. 3 showing details ofthe valve, and

FIG. 7 is a similar view showing the valve in the FIG. 5 position.

On the accompanying drawings the main body of my injector is shown atIll, being tubular in character and provided with a handle or grip 12.The body It) and handle 12 are preferably formed integral to prevent anypossibility of misalignment of parts as when made separately andconnected together. The near side of the handle as shown in FIG. 1however is open for assembly purposes and a cover plate 14 is, afterassembly, secured thereto as by a pair of screws 16.

Referring to FIG. 4, at the left end of the body it is a medicamentchamber 18 held in position by a retainer nut 39. A pin 19 and a keywayv2i prevent rotation of the medicament chamber 18 relative to the body10. The medicament chamber has a discharge passageway 29. Cooperatingtherewith is a discharge nose 22 having a minute discharge orifice 24from which the jet stream issues during the operation of the injector. Avalve 26 is rotatable in the medicament chamber 18 and controls flow ofmedicament as between the chamber and the discharge passageway 21), andbetween the chamber and a medicament tube 28 adapted to receivemedicament as from a bottle 36. A vent tube 32 extends from a filter 34into the medicament bottle to replace the medicament flowing therefromwith filtered air.

A hold-down pad 38 is provided for the bottle 36 and supported by aU-shaped rod 40 and a lock screw 42. The rod is slidable in a bracket 44mounted on the body 10 and may be locked in any desired position bymeans of the lock screw 42. Bottle-holding arms i5 extend from thebracket 44 to embrace the bottle 36.

The medicament chamber 18 has an extension 45 through which a springactuated plunger 48 is slidable. 'Ihe plunger is enlarged as at 56) andfurther enlarged into a spring cup 52. The spring cup is slidable in asleeve 54 that lines the body Eli and is held in position therein by aretainer nut 55. A spring barrel 56 is slid-able in the cup 52 and hasan O-ring seal 5-8 relative to the sleeve 54. A bleeder hole 5? isprovided through the wall of the sleeve 54 and the body It} for apurpose which will hereinafter appear.

Within the spring barrel 56 is a spring assembly 60 which may be eithera single spring, or two springs as illustrated with a spacer washer 62between them. The spring assembly 6% is precompressed to a predetermineddegree wd held in that condition by a head 64 on a bolt 66 threaded intothe enlargement 5% as at 68. A sleeve slides inside the spring barrel 56and has a shoulder 67 coacting with the head 64 when the parts are inthe position shown in FIG. 3. The sleeve 65 has an enlargement 6 9against an intnrned flange 71 of the spring barrel 56 to confine theright hand end of the spring assembly wherea the left hand end isconfined by the bottom of the spring cup 52.

A refill spring is provided surrounding the springactuate'd plunger 48and the enlargement 5t), and bearing against washers 72 and 74 which inturn bear against 3 the extension and a latch washer 73 positionedagainst the spring cup '2.

A medicament plunger 75 is slidable in the medicament chamber 18 and hasa shank St} entering a bore 82 of the plunger d8. A sleeve 7?, issecured in this bore and as shown by comparing FIGS. 4 and 5 the shank80 has some lost motion within the bore 82, being provided with anenlarged head to coact with the sleeve 78 to prevent the shank frombeing pulled out of the plunger for a purpose which will hereinafterappear. The shank 80 is split in the form of a cross and is of such sizethat the enlarged head at the right hand end thereof frictionallyengages in the bore 82.

T he sleeve es carries a roller 84 with which a cam 85 is adapted tocoact. The cam is mounted on a crank shaft 83 which is rotatable in apair of arms 9%} extending from a sleeve 91 held in position at theright hand end of the body ll? by a retainer nut 55. The sleeve 91 andthe arms 94} are thus stationary relative to the body and the handle 12.A crank 92 is secured to the crank shaft and terminates a crank handle94 and a valve-actuating pin $5. The pin 96 is adapted to coact with avalve lever $8 for oscillating the valve 26, and the valve lever has apair of stop shoulders 19% and 102 as shown in FlGS. 6 and 7.

A latch plate 1'64 is slidably mounted on a pair of pins 1% and biasedin an upward direction by a spring The latch plate 194 has a latchshoulder 1% adapted to coact with the latch washer 73 as shown in FIG.4. Both the latch plate washer 73 and the latch plate 1% are hardened tominimize wear.

A trigger 1-H} is pivotally mounted in the handle 12. and biased to theposition shown in FIG. 4 by a spring 112. The trigger normally coactswith a shoulder 114 on the latch plate 04 also as shown in FIG. 4.

Practical Operation In the operation of my multidose jet injector,starting with the parts in the positions shown in FIGS. 1, 2, 3 and 6,and assuming the medicament chamber 18 filled with medicament ahead ofthe plunger 76, the handle '12 is held in the right hand while the lefthand rotates the crank 32 counterclockwise in FIG. 1 a little more thanapproximately 195 whereupon the crank will assume the dot and dash lineposition shown in FIG. 3 with the pin 96 at the position shown in FIG.6. Several more degrees of rotation will bring the parts to the positionshown in F G. 4, the cam $6 having moved the roller 84 from the positionof FIG. 1 to the position of FIG. 4 and in so doing, imparting furthercompression to the spring as sembly as as can be seen by comparing FIG.4 with FIG. 3. The valve lever 98 in FIG. 4 has been moved about halfway from the position shown in FIG. 6 to the position shown in FIG. 7 byreason of the pin 96 engaging in a slot 99 thereof, and the springassembly is substantially fully compressed. Several more degrees ofrotation brings the parts to the position of FIG. 5 with the crank 92assuming the position indicated by the dot-anddash line 92 in FIG. 5. Bythis time the pin 95 has moved the valve lever 95 to the position shownin FIG. 7 and the valve 25 to the position shown in FIGS. 5 and 7. Thespring assembly is still latched in compressed position however as shownin FIG. 4 and ready for the injection.

The nose .22 is now placed in contact with the injection site and thetrigger ill pulled for removing its upper end from under the latchshoulder 114 so that the latch plate 164 will be propelled forwardly anddownwardly by the latch washer 73 against the latch shoulder 106 incooperation with the pins v1% in the slots in the latch plate as shownin FIG. 5. The slots are set at such angles as to permit the pressure ofthe spring assembly 68 against the latch washer 73 to move the latchplate downwardly against the bias of the spring 1%. Thereupon the springassembly will move the spring cup 52 and the plunger 48 forwardly untilthe plunger engages the medicament plunger 76, taking up the impactspace Y shown in FIG. 4 (and by arrowheads in FIG. 3), so that theinitial impact will build up a sudden high pressure surge-like dischargefrom the orifice 24 suflicient to puncture the epidermis and cause thejet to penetrate to some depth therebeneath. The pressure then drops oilwhen the impact has been spent and thereafter a steady follow- (throughpressure caused by the expansion of the spring assembly 6% forces themedicament plunger 76 forward: ly in the medicament chamber 18 to causea lower pressure follow-through jet to discharge the medicament throughthe puncture in the epidermis and the underlying cells and be dispersedat the level to winch the impactproduced jet penetrated.

FlG. 5 shows the impact space Y taken up, and when the medicamentplunger 76 reaches the forward end of the chamber 18 the spring assembly6!} will be expanded substantially as shown in FIG. 3 but the parts willbe in a forward position and ready for retraction to the initialposition of FIG. 3. Retraction is accomplished by swinging the valvelever 98 from the position of FIGS. 5 and 7 to the position of FIG. 6whereupon the handle 92 may be moved from the position 92 shown in FIG.5 to the initial position shown in FIGS. 1 and 2, and the solid lineposition in FIG. 3. This leaves the roller 84 free to be moved from theposition of FIG. 5 to the position of FIGS. 1 and 3 in response toexpansion of the refill spring 70 which will first take up the playbetween the enlarged head of the shank and the right hand end of thesleeve 78 and then retract the medicament plunger 76 in the chamber 18for drawing in another charge of medicament from the bottle 36 throughthe valve 26. Thereupon the parts are in the initial position and thelatch plate 194 is moved upwardly by the spring 168 to relatch itsshoulder 106 ahead of the latch washer 73, whereupon the above describedcycle may be repeated for another injection.

In FIG. 1, I illustrate how a somewhat smaller bottle 36 may be used inplace of the bottle 36 for only a few injections whereas the bottle 36would give many injections as for mass injections of soldiers and thelike. When my instrument is operated, shock to the parts is eliminatedby reason of the resistance to expansion of the springs 60 offered bythe medicament in the chamber 18 which can discharge only through theorifice 2.4. This regulates the speed of travel of the parts as thesprings expand, the total time of discharge being approximately onesecond. Protection against shock if the chamber '18 is empty is providedby the O-ring seal 58 in the sleeve 54 and the bleeder hole 59. The sealacts as a piston and air that is compressed within the spring barrel 56is forced out of the spring cup 52 and fiows to atmosphere through thebleeder hole. The size of the hole is such as to permit operation in ashorter period of time (for example three-fourths of a second) than thatrequired for an injection so as not to slow down the injecting stroke.

From the foregoing description, it is obvious that I have provided amultidose jet injector that can be oper ated by hand and does notrequire electric and/ or hydraulic power as in the previous patent andapplication above referred to.

Some changes may be made in the construction and arrangement of theparts of the multidose jet injector herein disclosed without departingfrom the real spirit and purpose of my invention, and it is my intentionto cover by my claims any modified forms of structure or use ofmechanical equivalents which may reasonably be included within theirscope.

I claim as my invention:

1. A multidose hypodermic injector comprising a body having therein amedicament chamber terminating in a nose containing an injectionorifice, a medicament plunger disposed within said chamber, a spring cupsupporting said medicament plunger, a spring barrel slidable relativethereto, a spring in said cup and barrel for advancing said plunger toeject medicament through said orifice, a latch for said spring cupcarried by said body, compressing means for said spring to preload itfor injection comprising a cam shaft rotatably carried by said body, acam thereon for moving said spring barrel relative to said body and alever for rotating said cam shaft and said cam, a valve which in fillingposition connects said medicament chamber to a source of medicament andin discharge position COBHCCS said medicament chamber to said nose andinjection orifice, said cam lever engaging said valve to move it fromfilling position to discharge position upon said cam lever completingits spring compressing movement, and means for releasing said latch.

2. A multidose hypodermic injector comprising a body having therein amedicament chamber terminating in a nose provided with an injectionorifice, a medicament plunger movable within said chamber, preloadedspring means for advancing said plunger to eject medicament through saidorifice comprising a cup and a barrel telescopically associated andcontaining said spring means, a latch for said barrel when saidpreloaded spring means is fully compressed, compressing means for saidspring means comprising a cam shaft rotatably carried by said body, acam thereon for moving said spring barrel relative to said body and acrank for rotating said cam shaft and said cam, a valve for connectingsaid medicament chamber to a source of medicament or to said nose andinjection orifice, said crank engaging said valve to move it from itssource of medicament position to its nose and injection orifice positonas said crank approaches its spring fully compressed position, and atrigger to retain said latch in latched position, said trigger beingmovable to a position releasing said latch.

3. A multidose hypodermic injector comprising a body having therein amedicament chamber terminating in a nose provided with an injectionorifice, a medicament plunger movable within said chamber, a spring cupsupporting said plunger, a spring barrel slidable in said spring cup,preloaded spring means within said spring cup and said spring barrel foradvancing said plunger to eject medicament through said orifice, a latchfor said preloaded spring means, said latch being carried by said bodyand coacting with said spring cup, comprising means for said springmeans to preload it for injection comprising a cam shaft rotatablysupported by said body, a cam thereon, a roller operatively connected tosaid spring barrel and engageable by the lobe of said cam for movingsaid spring barrel in the spring compressing direction and a crank forrotating said cam shaft and said cam, a valve for connecting saidmedicament chamber to a source of medicament or to said nose andinjection orifice, and a trigger for releasing said latch.

4. The injector of claim 3 wherein a lost motion connection is providedbetween said medicament plunger and said spring cup to provide for aninitial impact pressure as between said spring means and said medicamentplunger.

5. The injector of claim 2 wherein a lost motion connection is providedbetween said medicament plunger and said spring cup.

6. An injector instrument comprising a body defining at one end amedicament chamber having a discharge orifice, a plunger carried withinsaid body and entering said medicament chamber, a spring assembly formoving said plunger and thereby expelling medicament through saidorifice, said spring assembly comprising a pair of cuplike sleevestelescopically related to each other and slidable in said body, a co 1pression spring contained in said sleeves and connecting means betweenthe cup bottoms to retain said spring preloaded, a latch for said springassembly and carried by said body to lock said assembly in a positionslightly spaced from said plunger when the latter is in retractedposition, a roller carried by said spring assembly, a cam shaftrotatably carried by said body and having a cam coacting with saidroller, and a lever for rotating said cam shaft and cam for compressingsaid spring assembly whereby upon release of said latch said springassembly expands to impart an initial advancing force to said plungerand thereafter continues to apply advancing force for ejecting themedicament.

7. In an injector instrument, a body defining at one end a medicamentchamber having a discharge orifice, a plunger movable within said body,and entering said medicament chamber, a roller movable toward saidplunger, 2. spring assembly for moving said plunger and therebyexpelling medicament through said orifice, said spring as semblycomprising a of cup-like sleeves telescopically related to each otherand slidable in said body, a compression spring contained in saidsleeves and connecting means between the cup bottoms to retain saidspring preloaded, said spring assembly being interposed between saidplunger and said roller, a latch mounted at a predetermined point onsaid body adjacent said spring assembly to lock the same in a positionwith said spring assembly spaced from said plunger when the latter is inretracted position, and a cam carried by said body for engaging saidroller and moving it toward said plunger to compress said springassembly whereby upon release of said latch said spring assembly expandsto impart an initial impact force to said plunger and thereafter acontinuing advancing force thereto for ejecting the medicament.

8. The instrument of claim 7 which includes a retractor spring betweensaid spring assembly and said body.

9. The instrument of claim 3 which includes a retractor spring operableto move said spring cup to latched position upon the retrograde portionof said cam coacting with said roller.

10. The instrument of claim 7 having a valve and a supply of medicament,said valve in one position supplying medicament to said chamber and inanother position allowing medicament to be discharged therefrom throughsaid orifice, said cam having means engaging said valve to change itsposition from fill to discharge as said cam completes the operation ofcompressing said spring assembly and being operative to hold said springassembly compressed until release by said latch.

References Cited in the file of this patent UNITED STATES PATENTS2,669,230 Smoot Feb. 16, 1954 2,717,597 Hein Sept. 13, 1955 2,821,193Ziherl et al. Jan. 28, 1958 2,928,390 Venditty et a1 Mar. 15, 19603,051,173 Johnson et al. Aug. 28, 1962 FOREIGN PATENTS 1,049,564 FranceApr. 19, 1953 1,249,255 France Nov. 21, 1960 969,302 Germany May 22,1958

6. AN INJECTOR INSTRUMENT COMPRISING A BODY DEFINING AT ONE END AMEDICAMENT CHAMBER HAVING A DISCHARGE ORIFICE, A PLUNGER CARRIED WITHINSAID BODY AND ENTERING SAID MEDICAMENT CHAMBER, A SPRING ASSEMBLY FORMOVING SAID PLUNGER AND THEREBY EXPELLING MEDICAMENT THROUGH SAIDORIFICE, SAID SPRING ASSEMBLY COMPRISING A PAIR OF CUPLIKE SLEEVESTELESCOPICALLY RELATED TO EACH OTHER AND SLIDABLE IN SAID BODY, ACOMPRESSION SPRING CONTAINED IN SAID SLEEVES AND CONNECTING MEANSBETWEEN THE CUP BOTTOMS TO RETAIN SAID SPRING PRELOADED, A LATCH FORSAID SPRING ASSEMBLY AND CARRIED BY SAID BODY TO LOCK SAID ASSEMBLY IN APOSITION SLIGHTLY SPACED FROM SAID PLUNGER WHEN THE LATTER IS INRETRACTED POSITION, A ROLLER CARRIED BY SAID SPRING ASSEMBLY, A CAMSHAFT ROTATABLY CARRIED BY SAID BODY AND HAVING A CAM COACTING WITH SAIDROLLER, AND A LEVER FOR ROTATING SAID CAM SHAFT AND CAM FOR COMPRESSINGSAID SPRING ASSEMBLY WHEREBY UPON RELEASE OF SAID LATCH SAID SPRINGASSEMBLY EXPANDS TO IMPART AN INITIAL ADVANCING FORCE TO SAID PLUNGERAND THEREAFTER CONTINUES TO APPLY ADVANCING FORCE FOR EJECTING THEMEDICAMENT.